Visual studio code debug tool for python unit test does not show debug tools, when extra library is imported

For pure Django tests, visual studio code easily discovers my tests so i can debug them:

from django.test import TestCase


class SomethingTest(TestCase):
    def setUp(self) -> None:
        return super().setUp()

    def test_something(self):
        self.assertEqual(4, 4)

But when i add some Django-rest-framework libraries - debug tools disappear:

from django.test import TestCase
from rest_framework.test import APIClient

class BoringTest(TestCase):

    def setUp(self) -> None:
        return super().setUp()

    def test_boring(self):
        self.assertEqual(4, 4)

How can I setup vs code unit-test debug tools so i can use rest_framework?